Spabk-pltjg



W. E. SCHUBERT.

SPARK PLUG.

APPLXCATION FILED IAN-6.1919.

Patented Aug. 19, 1919.

6 2 INVENTOR OFFICE.

WALTER E. SGHUBERT, OF BROOKLYN, NEW YORK.

SPARK-PLUG.

Specification of Letters Patent.

Patented Aug. 19, 1919.

Application filed January 6, 1919. Serial No. 269,848.

To all whom it may concern:

Be it known that I, WALTER E. SCHUBERT, a citizen of the United States, residing in the borough of Brooklyn, city of New York, county of Kings, and State of New York,

have invented certain new and useful Improvements in Spark-Plugs, of which the following is a specification.

This invention relates to spark plugs, its object being to produce a spark plug which when foul can be quickly cleaned without removing it from the compression cylinder.

In the accompanying drawings forming a part hereof,

Figure 1 is a central lengthwise sectional view of one form of spark plug embodying this invention.

Fig. 2 is a perspective view of the innerend ground electrode forming wall of the spark plug casing adjacent my new ground wall scraper.

In the drawings, casing 1, its cap 2, ring 3, cushioning rings 4, and plug 5 of insulating material having a lengthwise central bore for the insulated electrode rod 6 are of -well known form and may be of various other forms for the purposes of this invention in accordance with which the insulated electrode rod 6 at its inward end is provided with one or more arms 7, two diametrically opposed arms being shown, which may .be held out of contact with the inner end wall 8 of the casing 1, such inner end forming the ground electrode in order to form the proper air gap at 9 as shown in Fig. l; or which may be brought into physical contact with the end wall-8 when it is foul 'for scraping such end wall free of such deposit as would interfere with the sparking. In the form shown, the bottom end of this insulation 6 is flush with the ground wall 8, and the scraper is shown in a form to scrape both the ground wall 8 and the other bottom end of the insulation 5. The armed insulated electrode rod 6 may be called the ground wall scraper. The free end of each arm overlaps the ground wall and is opposed thereto.

The upper end of the insulating plug 5 is provided with an externally threaded collar 10 for reception of an internally threaded spring adjusting cap 11 through the upper wall of which the electrode rod 6 ex or other suitable material for preventing leak of gases in the motor cylinder past the rod; then through an internally-threaded nut 13 and a lock nut 13 if it is desired. The upper end portion of the electrode rod is threaded at 14 at and above the insulating plug 5 within and outside of the adjusting cap between the closed upper end of which and the nut 13 a stiff coiled spring 15 is located, its bottom end resting on a-threaded nut and its upper end abutting against the end wall of the cap. The projecting end'of the insulated electrode rod is provided with a nut 16 for clamping a lead, not shown, to the capped end of the spark plug and with a knurled head 17 fixed to the rod for turning it in order to raise the electric contactscraper into scraping position. The head 18 is shown fixed inpla'ce by a pin 19. The cap 11 serves for adjustment of the spring tension on the nut 13, such tension keeping the nut from turning and also keeping, it compressively on the compression-holding washer 12, when the rod 6 is turned to bring the electric contact scraper into physical contact with the wall 8 to clean it, and from turning when the rod is turned in the other direction to move the contact scraper out of physical contact with wall 8 for'establishment of a jump spark gap of regulable extent at 9.

The under end surface of the metal casing which forms the continuously flat ground wall 8 and every portion of this wall 8 forms a terminal between which and an opposed scraper arm 7 a jump-spark will occur. An advantage of this construction is first that it is wholly unnecessary carefully to position the arms 7 in opposition to any particular part of the ground wall as would be the case if the wall 8 were provided with downwardly projecting sparking terminals in opposition to which the arms 7 would have to be positioned with certainty before the plug would be efiicient in use; and as these spark plugs have their inward ends obscured, the necessity of the careful positioning would be very objectionable when the spark plugs were used in internal-combustion engines. Secondly, the construction has the substantial advantage of a great multiplicity of jump-spark available surfaces in consequence of all portions of the wall 8 being in a single plane and in a circle, and any haphazard positionin of the arms 7 being alone required to e ect the necessary Y 13 not only secures the compression because the spring pressure against it serves as a practically stationary bearin through which the electrode rod 6 may fie turned either for establishment of the requisite air gap or for thoroughly cleaning the/ground 7 wall 8. Another advantage of the construction shown, although I'do not wish unduly to emphasize the point, .is that as shown the under or inward end of the insulating plug I 5is flush with the ground wall so that there' is no space for accumulation of anything more than a coating of carbonaceous deposit on the, flush surfaces of the alined ground wall 8 and inner end of the insulation plug 5.

Byturning the nut 16 on cap 11, the rod 6 is turned upward against the tension spring 15, turnlng in nut 13, or in nut 13 and the lock nutl3 -if the latter isused, and brings the arms 7 into scraping position. But the rod Gmay be pulled upward against the tension of spring 15, when the members are in the position shown in Fig.

1,..the-bore through the top of cap 11 not being in threaded engagement with the thread on the rod 6. The first way of using the device for scraping is the better unless the accumulation on the wall 8 is very slight.

What I claim is:

A spark-plug comprising a casing which is a conductor for electricity and 21 thereinmounted insulation plug having a lengthwise bore, the inner end of the casing being continuously flatwithout dependent projections and forming a ground wall; a rotatable electrode rod mounted in the bore of the insulation plug and provided at its lower end with an exteriorly accessible ground wall scraper; a compression-holding disk of yielding material around the rod and bearmg on the upper end of the insulation plug,

the upper end portion of the electrode rod being threaded; a nut on such threaded por tion of the rod, and bearing compresslbly on the compression-holding disk; a coiled spring around the upper portion of the rod positioned to bear against said nut; an internally-threaded spring-adjusting cap having a screw connection with the upper end of the insulation plug, such ca having a hole for passage therethrough o? end portion of said rod; and means exteriorly of said cap for connection of a lead. In testimony whereof I have hereunto set my hand this 2d da of January, 1919.

WAL ER E.SCHUBERT.

the upper- 

